Identification Documents
Identification documents (hereafter “ID documents”) play a critical role in today's society. One example of an ID document is an identification card (“ID card”). ID documents are used on a daily basis—to prove identity, to verify age, to access a secure area, to evidence driving privileges, to cash a check, and so on. Airplane passengers are required to show an ID document during check in, security screening and prior to boarding their flight. In addition, because we live in an ever-evolving cashless society, ID documents are used to make payments, access an automated teller machine (ATM), debit an account, or make a payment, etc.
(For the purposes of this disclosure, ID documents are broadly defined herein, and include, e.g., credit cards, bank cards, phone cards, passports, driver's licenses, network access cards, employee badges, debit cards, security cards, visas, immigration documentation, national ID cards, citizenship cards, social security cards, security badges, certificates, identification cards or documents, voter registration cards, police ID cards, border crossing cards, legal instruments, security clearance badges and cards, gun permits, gift certificates or cards, membership cards or badges, etc., etc. Also, the terms “document,” “card,” “badge” and “documentation” are used interchangeably throughout this patent application.).
An exemplary ID document can comprise a core layer (which can be pre-printed), such as a light-colored, opaque material (e.g., TESLIN (available from PPG Industries), polycarbonate, polyethylene terephthalate (PET), polyvinyl chloride (PVC) material, etc.). The core is laminated with a transparent material, such as clear PC, PET, or PVC to form a so-called “card blank”. Information, such as variable personal information (e.g., photographic information), is printed on the card blank using a method such as Dye Diffusion Thermal Transfer (“D2T2”) printing (described further in commonly assigned U.S. Pat. No. 6,066,594, which is incorporated herein by reference in its entirety), laser printing, Indigo printing, Inkjet printing, etc. The information can, for example, comprise an indicium or indicia, such as the invariant or nonvarying information common to a large number of identification documents, for example the name and logo of the organization issuing the documents. The information may be formed by any known process capable of forming the indicium on the specific core material used.
To protect the information that is printed, an additional layer of transparent overlaminate can be coupled to the card blank and printed information, as is known by those skilled in the art. Illustrative examples of usable materials for overlaminates include biaxially oriented polyester or other optically clear durable plastic film (e.g., polycarbonate, PET, etc.)
Many types of identification cards and documents, such as driving licenses, national or government identification cards, bank cards, credit cards, controlled access cards and smart cards, carry thereon certain items of information which relate to the identity of the bearer. Examples of such information include name, address, birth date, signature and photographic image; the cards or documents may in addition carry other variant data (i.e., data specific to a particular card or document, for example an employee number) and invariant data (i.e., data common to a large number of cards, for example the name of an employer). All of the cards described above will hereinafter be generically referred to as “ID documents”.
In the foregoing discussion, the use of the word “ID document” is broadly defined and intended to include all types of ID documents, including (but not limited to), documents, magnetic disks, credit cards, bank cards, phone cards, stored value cards, prepaid cards, smart cards (e.g., cards that include one more semiconductor chips, such as memory devices, microprocessors, and microcontrollers), contact cards, contactless cards, proximity cards (e.g., radio frequency (RFID) cards), passports, driver's licenses, network access cards, employee badges, debit cards, security cards, visas, immigration documentation, national ID cards, citizenship cards, social security cards, security badges, certificates, identification cards or documents, voter registration and/or identification cards, police ID cards, border crossing cards, security clearance badges and cards, legal instruments, gun permits, badges, gift certificates or cards, membership cards or badges, and tags. Also, the terms “document,” “card,” “badge” and “documentation” are used interchangeably throughout this patent application.). In at least some aspects of the invention, ID document can include any item of value (e.g., currency, bank notes, and checks) where authenticity of the item is important and/or where counterfeiting or fraud is an issue.
In addition, in the foregoing discussion, “identification” at least refers to the use of an ID document to provide identification and/or authentication of a user and/or the ID document itself. For example, in a conventional driver's license, one or more portrait images on the card are intended to show a likeness of the authorized holder of the card. For purposes of identification, at least one portrait on the card (regardless of whether or not the portrait is visible to a human eye without appropriate stimulation) preferably shows an “identification quality” likeness of the holder such that someone viewing the card can determine with reasonable confidence whether the holder of the card actually is the person whose image is on the card. “Identification quality” images, in at least one embodiment of the invention, include covert images that, when viewed using the proper facilitator (e.g., an appropriate light or temperature source), provide a discernable image that is usable for identification or authentication purposes.
Of course, it is appreciated that certain images may be considered to be “identification quality” if the images are machine readable or recognizable, even if such images do not appear to be “identification quality” to a human eye, whether or not the human eye is assisted by a particular piece of equipment, such as a special light source. For example, in at least one embodiment of the invention, an image or data on an ID document can be considered to be “identification quality” if it has embedded in it machine-readable information (such as digital watermarks or steganographic information) that also facilitate identification and/or authentication.
The terms “indicium” and indicia as used herein cover not only markings suitable for human reading, but also markings intended for machine reading. Especially when intended for machine reading, such an indicium need not be visible to the human eye, but may be in the form of a marking visible only under infra-red, ultra-violet or other non-visible radiation. Thus, in at least some embodiments of the invention, an indicium formed on any layer in an identification document (e.g., the core layer) may be partially or wholly in the form of a marking visible only under non-visible radiation. Markings comprising, for example, a visible “dummy” image superposed over a non-visible “real” image intended to be machine read may also be used.
Information Contained on Identification Documents
As those skilled in the art know, ID documents such as drivers licenses can contain information such as a photographic image, a bar code (which may contain information specific to the person whose image appears in the photographic image, and/or information that is the same from ID document to ID document), variable personal information, such as an address, signature, and/or birthdate, biometric information associated with the person whose image appears in the photographic image (e.g., a fingerprint), a magnetic stripe (which, for example, can be on the a side of the ID document that is opposite the side with the photographic image), and various security features, such as a security pattern (for example, a printed pattern comprising a tightly printed pattern of finely divided printed and unprinted areas in close proximity to each other, such as a fine-line printed security pattern as is used in the printing of banknote paper, stock certificates, and the like).
An exemplary ID document can comprise a substrate or core layer (which can be pre-printed), such as a light-colored, opaque material (e.g., polycarbonate, TESLIN (available from PPG Industries) polyvinyl chloride (PVC) material, etc). In certain instances and with certain printing or information forming technologies, variable or personalized data can be formed directly on the substrate or core layer. In other instances, the core layer may be coated and/or laminated with another material to enable printing or other methods of forming information. For example, the substrate or core layer can be laminated with a transparent material, such as clear polycarbonate or PVC to form a so-called “card blank”.
Information, such as variable personal information (e.g., photographic information), can then formed on the card blank using one or more methods, such as laser xerography, Indigo, intaglio, laser engraving or marking, inkjet printing, thermal or mass transfer printing, dye diffusion thermal transfer (“D2T2”) printing, (described in commonly assigned U.S. Pat. No. 6,066,594, which is incorporated herein by reference in its entirety.), etc. The information can, for example, comprise an indicium or indicia, such as the invariant or nonvarying information common to a large number of identification documents, for example the name and logo of the organization issuing the documents. The information may be formed by any known process capable of forming the indicium on the specific core material used.
Certain technologies for forming or printing information may require further protection of the information, so an additional layer of transparent overlaminate can be coupled to the core layer or card blank and the information printed thereon, as is known by those skilled in the art. Illustrative examples of usable materials for overlaminates include polycarbonate, biaxially oriented polyester, or other optically clear durable plastic film.
Manufacture and Printing Environments
Commercial systems for issuing ID documents are of two main types, namely so-called “central” issue (CI), and so-called “on-the-spot” or “over-the-counter” (OTC) issue.
CI type ID documents are not immediately provided to the bearer, but are later issued to the bearer from a central location. For example, in one type of CI environment, a bearer reports to a document station where data is collected, the data are forwarded to a central location where the card is produced, and the card is forwarded to the bearer, often by mail. Another illustrative example of a CI assembling process occurs in a setting where a driver passes a driving test, but then receives her license in the mail from a CI facility a short time later. Still another illustrative example of a CI assembling process occurs in a setting where a driver renews her license by mail or over the Internet, then receives a drivers license card through the mail.
In contrast, a CI assembling process is more of a bulk process facility, where many cards are produced in a centralized facility, one after another. (For example, picture a setting where a driver passes a driving test, but then receives her license in the mail from a CI facility a short time later. The CI facility may process thousands of cards in a continuous manner.).
Centrally issued identification documents can be produced from digitally stored information and generally comprise an opaque core material (also referred to as “substrate”), such as paper or plastic, sandwiched between two layers of clear plastic laminate, such as polyester, to protect the aforementioned items of information from wear, exposure to the elements and tampering. The materials used in such CI identification documents can offer the ultimate in durability. In addition, centrally issued digital identification documents generally offer a higher level of security than OTC identification documents because they offer the ability to pre-print the core of the central issue document with security features such as “micro-printing”, ultra-violet security features, security indicia and other features currently unique to centrally issued identification documents.
In addition, a CI assembling process can be more of a bulk process facility, in which many cards are produced in a centralized facility, one after another. The CI facility may, for example, process thousands of cards in a continuous manner. Because the processing occurs in bulk, CI can have an increase in efficiency as compared to some OTC processes, especially those OTC processes that run intermittently. Thus, CI processes can sometimes have a lower cost per ID document, if a large volume of ID documents are manufactured.
In contrast to CI identification documents, OTC identification documents are issued immediately to a bearer who is present at a document-issuing station. An OTC assembling process provides an ID document “on-the-spot”. (An illustrative example of an OTC assembling process is a Department of Motor Vehicles (“DMV”) setting where a driver's license is issued to person, on the spot, after a successful exam.). In some instances, the very nature of the OTC assembling process results in small, sometimes compact, printing and card assemblers for printing the ID document. It will be appreciated that an OTC card issuing process is by its nature can be an intermittent—in comparison to a continuous—process.
OTC identification documents of the types mentioned above can take a number of forms, depending on cost and desired features. Some OTC ID documents comprise highly plasticized poly(vinyl chloride) or have a composite structure with polyester laminated to 0.5-2.0 mil (13-51 .mu.m) poly(vinyl chloride) film, which provides a suitable receiving layer for heat transferable dyes which form a photographic image, together with any variant or invariant data required for the identification of the bearer. These data are subsequently protected to varying degrees by clear, thin (0.125-0.250 mil, 3-6 .mu.m) overlay patches applied at the printhead, holographic hot stamp foils (0.125-0.250 mil 3-6 .mu.m), or a clear polyester laminate (0.5-10 mil, 13-254.mu.m) supporting common security features. These last two types of protective foil or laminate sometimes are applied at a laminating station separate from the printhead. The choice of laminate dictates the degree of durability and security imparted to the system in protecting the image and other data.
UV Security Features in ID Documents
One response to the problem of counterfeiting ID documents has involved the integration of verification features that are difficult to copy by hand or by machine, or which are manufactured using secure and/or difficult to obtain materials. One such verification feature is the use in the card of a signature of the card's issuer or bearer. Other verification features have involved, for example, the use of watermarks, biometric information, microprinting, covert materials or media (e.g., ultraviolet (UV) inks, infrared (IR) inks, fluorescent materials, phosphorescent materials), optically varying images, fine line details, validation patterns or marking, and polarizing stripes. These verification features are integrated into an identification card in various ways and they may be visible or invisible (covert) in the finished card. If invisible, they can be detected by viewing the feature under conditions which render it visible. At least some of the verification features discussed above have been employed to help prevent and/or discourage counterfeiting.
Covert security features are those features whose presence is not visible to the user without the use of special tools (e.g., UV or IR lights, digital watermark readers) or knowledge. In many instances, a covert security feature is normally invisible to a user. Some technologies that involve invisible features require the use of specialized equipment, such as a detector or a device capable of reading digital watermarks. One type of covert security feature is the printing of information (images, designs, logos, patterns, text, etc.) in a material that is not visible under normal lighting conditions, but can be viewed using a special non-visible light source, such as an ultraviolet (UV) or infrared (IR) light source. Use of UV and/or IR security features can be advantageous because although the devices (for example, UV and/or IR light sources) required to see and use such features are commonly available at a reasonable cost, the ability to manufacture and/or copy at least some implementations of such features is far less common and can be very costly. UV and IR based covert security features thus can help deter counterfeiters because the features cannot be copied by copiers or scanners and are extremely difficult to manufacture without the requisite know-how, equipment, and materials.
For example, the assignee of the present invention has developed and marketed a proprietary product called PolaPrime-UV™. PolaPrime-UV™ is a type of security feature. One application of PolaPrime-UV™ is for full color photo quality printing of fixed (i.e., not variable data) fluorescent images. The artwork that can be printed using PolaPrime-UV™ includes many images that can be produced with a combination of red, green, and blue phosphors. Under the appropriate light (e.g., a light source capable of providing UV light), the effect seen when viewing an image printed with PolaPrime-UV™ is similar in appearance to a television screen in that the image is formed by emission of light rather than reflection as with ink on paper. To date, PolaPrime-UV™ has been a reliable authenticator for genuine identification documents.
Printing of Covert Materials such as UV
Many images, such as color images, are formed by subtractive techniques, e.g., light is passed through absorbing dyes and the combination of dyes produce an image by sequentially subtracting cyan, magenta, and yellow components to provide the full color image. In the case of a UV fluorescing image, the UV image is formed by light emitting from fluorescing dyes or pigments as they are activated by a UV light or energy source. A UV image can be imparted to an ID document via methods such as thermal transfer or D2T2. In certain printing environments (such as printing environments that use laser printing and/or laser xerography), covert images can be imparted to documents through the toners used for printing.
Laser Printing and Toners for Laser Printing
Laser printers operate using principles of static electricity. A cylinder or drum revolves to build up and electrostatic charge. A very small laser beam is pointed towards the cylinder/drum, and the laser beam discharges the surface of the cylinder/drum in a pattern corresponding to the pattern of indicia (e.g., letters, images) to be printed. This results in the surface of the cylinder/drum having positively and negatively charged areas. A developer roller (also referred to as a pick up transfer roller) then picks up toner from a toner hopper. The medium being printed (e.g., paper, an identification document, etc.) is passed through the printer and is charged with a charge opposite to that of the toner on the drum, such that the toner is transferred from the drum to the paper. The medium being printed then passes through heated rollers to fuse the toner to the medium. Color laser printers can make multiple passes through this process, to mix the different color toners.
Toners, for at least some printers, consists of a very fine powder that is charged so that it clings only to the areas of the cylinder/drum having a charge opposite to that of the toner (e.g., positively charged toner clings only to negatively charged surface areas of cylinder/drum, and vice versa). Such toners typically comprise at least a binder resin and a colorant. Optionally, toners can include additional components such as external surface additives, magnetic particles, and/or filler material. Preferably, all of the components of a given toner are capable of being electrostatically charged so that they will stick to the selected areas scanned by the laser light beam in the laser printing process or otherwise exposed in the photocopying process.
The binder resin (also referred to, for purposes of use with toners, as an encapsulant) is used to encapsulate the pigments in the colorant into toner particles. Examples of materials that can be used as binders for toners include polymers, copolymers, polyolefins, other hydrocarbon polymers, or styrene. The colorant may include pigments such as carbon black, color or colorless dyes, covert pigments (e.g., UV and/or IR pigments), etc. External surface additives, which are generally added in small amounts, can include silica, titanium dioxide, zinc stearate, etc.
Magnetic particles (e.g., magnetite) can be used to evenly distribute the toner particles on the developer roller. As known to those skilled in the art, magnetite particles can act like magnetic “fingers” that enable charged toner particles to stick onto the fingers and cause the toner particles to be evenly distributed on a pickup transfer roller. Filler material which provides lubrication properties to the toner and melt upon heating and fusing to bond the toner particles to the printed media (paper or transparent foils). The filler materials can, for example, be materials like acrylic copolymers that are highly cross linked and have relatively low melting point (below 100 degrees C.). Examples of filler materials include polypropylene, polyethylene, etc., in micro-crystalline form (micro-ground to submicron sizes). Filler material provides lubrication properties and can help reduce agglomeration of the toner particles. In addition, filler material can melt upon fusing to help bond the toner material to the medium to which it is being printed.
Because toners can be used for laser printing, copying, xerographic printing, the availability of toners made using covert pigments (referred to herein as “covert toners”) has the potential to add covert printing capability to laser printing. Further information about covert toners can be found in U.S. Pat. No. 5,714,291, entitled “System for Authenticating Printed or Reproduced Documents,” which is hereby incorporated by reference.
We have found, however, that identification documents printed using at least some typical covert pigments (e.g., UV pigments) do not perform well under some types of test conditions, such as some testing conditions in the American National Standards Institute (ANSI) National Committee for International Technology Standards (NCITS) 322 document for Card Durability Test Methods Working Paper (available from the American National Standards Institute in Washington, D.C.) For example, identification documents printed using at least some covert pigments fail to perform well under all of the NCITS 322 testing extremes, especially tests such as Surface Abrasion, Image Abrasion, Temperature and Humidity tests (including Temperature and Humidity induced dye migration), Ultraviolet (UV) Light Exposure Stability, Daylight Image Stability (Xenon Arc), and Laundry Test. NCITS 322 is designed to represent extremes of real conditions to which the printed documents may be subjected. Because many large government programs (LGPs) such as issuers of driver's licenses require NCITS 322 compliance, these types of performance failures of covert pigments need to be reduced or eliminated if covert toners are to be used successfully in printing of these types of identification documents.
In particular, we have found several performance problems with some covert pigments, covert inks, and covert toners (toners containing so-called “covert” pigments —pigments that, when mixed into the toner, produce a printed image that is visible only under certain conditions, such as under ultraviolet (UV) and/or infrared (IR) illumination).
One aspect of the invention is a covert material for printing onto a printing medium. This covert material comprises a covert pigment, and a binder encapsulating the covert pigment into a particle. The binder comprises at least one of cellulose acetate butyrate (CAB), butyral vinyl acetate, acetyl butyrate, and acetate butyrate. In an alternative embodiment, the binder comprises at least one of polyester, polyolefin, acetyl butyrate, acetate butyrate, polystyrene copolymer, and polystyrene-polyvinylpyridine.
The covert material may further comprise a colorant, a surface additive, and a magnetic particle, and may be part of a toner or ink. In a particular toner embodiment, the toner includes the covert material and a sub-component material comprising at least one of cellulose acetate butyrate (CAB), butyral vinyl acetate, acetyl butyrate, and acetate butyrate. In this embodiment, the binder for the covert material and the subcomponent of the toner comprise substantially the same material.
The covert material may be constructed and arranged to be printed using a printer having a predetermined resolution, where the particle has a size that is substantially the same as the size of a single pixel or dot printed using the predetermined resolution.
Another aspect of the invention is a method to prepare a covert material for printing comprising providing a covert pigment, and encapsulating the covert pigment into a binder to form a particle, where the binder comprises at least one of cellulose acetate butyrate (CAB), butyral vinyl acetate, acetyl butyrate, and acetate butyrate. The covert material is then mixed into a toner or an ink. In an alternative embodiment, the binder comprises at least one of polyester, polyolefin, acetyl butyrate, acetate butyrate, polystyrene copolymer, and polystyrene-polyvinylpyridine.
Another aspect of the invention is a method to prepare a covert material for printing. This method comprises mixing a binder with a first solvent to form a binder-solvent mixture, the binder comprising at least one of cellulose acetate butyrate (CAB), butyral vinyl acetate, acetyl butyrate, and acetate butyrate; encapsulating a covert pigment with the binder-solvent mixture; grinding the encapsulated covert pigment into a particle having a predetermined size; and mixing the particle into a second solvent.
The covert material is used to make an identification card. In one example of such a card, the card comprises a core layer, and a covert indicium printed onto the core layer using a covert printing medium. The covert printing medium comprises a covert pigment and a binder as summarized above. Alternatively, the covert indicium is printed on a substantially transparent layer affixed to the core layer.
Additional aspects of the invention are a method and structure for improving the stability of a covert pigment on printed object. The method comprises applying an undercoat of varnish to a substrate; and printing a covert pigment onto the undercoat. The undercoat forms an oxygen and/or water barrier between the covert pigment and the substrate. An overcoat using the same or different material as the undercoat may be used to encapsulate the covert pigment. This is particularly advantageous in documents that have a porous substrate and use covert inks that are susceptible to degradation when exposed to oxygen or water. A document structure includes a substrate, an undercoat and a covert pigment printed on the undercoat. Examples include a document with a substrate preprinted with an undercoat, fixed or variable information (e.g., personal information of the bearer) printed on the undercoat, and an overcoat of varnish, lacquer or overlaminate.